Hard disc drives have traditionally employed electromagnetic transducers that are spaced from a rapidly spinning rigid disc by a thin layer of air that moves with the disc surface. Such a spacing is believed to be important in avoiding damage between the rapidly spinning disc and the transducer, which is constructed with an aerodynamic “slider” designed to “fly” slightly above the disc surface, buoyed by the moving air layer. This spacing or fly height, however, limits the density with which data can be stored and lowers the resolution and amplitude with which data can be retrieved.
Currently, a liquid lubricant layer is placed on top of the magnetic recording media to reduce friction and wear caused by possible head-disc contact. The lubricants being used now are perfluoropolyethers, including Fomblin® Z and Y lubricants from Ausimont S.p.A., Krytox® lubricants from E. I. du Pont de Nemours, and Demnum® lubricants from Daikin America, Inc. When liquid lubricants are used in a hard disc drive, stiction, spin-off and lubricant transfer from the disc to the recording head may occur and thus reduce the reliability of head-disc interface.
Heat Assisted Magnetic Recording (HAMR) has been proposed recently to deliver one terabit per square inch (Tbpsi) data density. In HAMR, the disc surface will be heated to 400° C. or above by laser irradiation. Existing liquid lubricants cannot survive this temperature. Therefore, it is necessary to develop a lubricant with higher thermal stability. Sputtered polytetrafluoroethylene (PTFE) has been shown to be a promising candidate for this purpose.
To achieve higher data density in magnetic recording, the head fly height has been reduced. Currently, the head fly height is below 10 nm. This small head-disc spacing increases the possibility of head-media contact. Liquid lubricants can flow back after they are removed from their original position. Solid lubricants have been proposed for use on the surface of recording media. However, once solid lubricants are removed from the original position, they are gone permanently.
Therefore, there is a need for a way to reduce the wear rate for a solid-lubricated media.